The 3090’s Google integration is a bit strange.
You have to add “Robot Conga” found under the explore section of Google Assistant (not under add devices of Google home).
Instead of appearing as a device it operates as a chatbot, so you have to say exactly: “Hey Google, Ask robot conga to start/stop cleaning” or “Ask robot conga to charge”.
You can then set up a custom routine in Google home such as:
When I say - Start cleaning, Clean the floor, floor needs cleaning
Assistant will - Ask robot conga to start cleaning, Say: Ok cleaning started
An interesting option for HA could be emulating the supplied remote which seems to use some basic 2.4gHz protocol, similar to something like ZigBee or milighs